1 files changed, 132 insertions, 0 deletions
diff --git a/src/mercury/include/mercury_thread_spin.h b/src/mercury/include/mercury_thread_spin.h
new file mode 100644
index 0000000..36ce5f8
--- /dev/null
+++ b/src/mercury/include/mercury_thread_spin.h
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2013-2020 Argonne National Laboratory, Department of Energy,
+ *                    UChicago Argonne, LLC and The HDF Group.
+ * All rights reserved.
+ *
+ * The full copyright notice, including terms governing use, modification,
+ * and redistribution, is contained in the COPYING file that can be
+ * found at the root of the source code distribution tree.
+ */
+
+#ifndef MERCURY_THREAD_SPIN_H
+#define MERCURY_THREAD_SPIN_H
+
+#include "mercury_util_config.h"
+
+#include "mercury_thread_annotation.h"
+
+#if defined(_WIN32)
+#include <windows.h>
+typedef volatile LONG hg_thread_spin_t;
+#elif defined(HG_UTIL_HAS_PTHREAD_SPINLOCK_T)
+#include <pthread.h>
+typedef pthread_spinlock_t HG_LOCK_CAPABILITY("spin") hg_thread_spin_t;
+#else
+/* Default to hg_thread_mutex_t if pthread_spinlock_t is not supported */
+#include "mercury_thread_mutex.h"
+typedef hg_thread_mutex_t HG_LOCK_CAPABILITY("mutex") hg_thread_spin_t;
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Initialize the spin lock.
+ *
+ * \param lock [IN/OUT]         pointer to lock object
+ *
+ * \return Non-negative on success or negative on failure
+ */
+HG_UTIL_PUBLIC int hg_thread_spin_init(hg_thread_spin_t *lock);
+
+/**
+ * Destroy the spin lock.
+ *
+ * \param lock [IN/OUT]         pointer to lock object
+ *
+ * \return Non-negative on success or negative on failure
+ */
+HG_UTIL_PUBLIC int hg_thread_spin_destroy(hg_thread_spin_t *lock);
+
+/**
+ * Lock the spin lock.
+ *
+ * \param lock [IN/OUT]         pointer to lock object
+ */
+static HG_UTIL_INLINE void hg_thread_spin_lock(hg_thread_spin_t *lock) HG_LOCK_ACQUIRE(*lock);
+
+/**
+ * Try locking the spin lock.
+ *
+ * \param mutex [IN/OUT]        pointer to lock object
+ *
+ * \return Non-negative on success or negative on failure
+ */
+static HG_UTIL_INLINE int hg_thread_spin_try_lock(hg_thread_spin_t *lock)
+    HG_LOCK_TRY_ACQUIRE(HG_UTIL_SUCCESS, *lock);
+
+/**
+ * Unlock the spin lock.
+ *
+ * \param mutex [IN/OUT]        pointer to lock object
+ */
+static HG_UTIL_INLINE void hg_thread_spin_unlock(hg_thread_spin_t *lock) HG_LOCK_RELEASE(*lock);
+
+/*---------------------------------------------------------------------------*/
+static HG_UTIL_INLINE void
+hg_thread_spin_lock(hg_thread_spin_t *lock) HG_LOCK_NO_THREAD_SAFETY_ANALYSIS
+{
+#if defined(_WIN32)
+    while (InterlockedExchange(lock, EBUSY)) {
+        /* Don't lock while waiting */
+        while (*lock) {
+            YieldProcessor();
+
+            /* Compiler barrier. Prevent caching of *lock */
+            MemoryBarrier();
+        }
+    }
+#elif defined(HG_UTIL_HAS_PTHREAD_SPINLOCK_T)
+    (void)pthread_spin_lock(lock);
+#else
+    hg_thread_mutex_lock(lock);
+#endif
+}
+
+/*---------------------------------------------------------------------------*/
+static HG_UTIL_INLINE int
+hg_thread_spin_try_lock(hg_thread_spin_t *lock) HG_LOCK_NO_THREAD_SAFETY_ANALYSIS
+{
+#if defined(_WIN32)
+    return InterlockedExchange(lock, EBUSY);
+#elif defined(HG_UTIL_HAS_PTHREAD_SPINLOCK_T)
+    if (pthread_spin_trylock(lock))
+        return HG_UTIL_FAIL;
+
+    return HG_UTIL_SUCCESS;
+#else
+    return hg_thread_mutex_try_lock(lock);
+#endif
+}
+
+/*---------------------------------------------------------------------------*/
+static HG_UTIL_INLINE void
+hg_thread_spin_unlock(hg_thread_spin_t *lock) HG_LOCK_NO_THREAD_SAFETY_ANALYSIS
+{
+#if defined(_WIN32)
+    /* Compiler barrier. The store below acts with release semantics */
+    MemoryBarrier();
+    *lock = 0;
+#elif defined(HG_UTIL_HAS_PTHREAD_SPINLOCK_T)
+    (void)pthread_spin_unlock(lock);
+#else
+    hg_thread_mutex_unlock(lock);
+#endif
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MERCURY_THREAD_SPIN_H */